(AP) – Missouri Gov. Jay Nixon declared a state of emergency Monday and activated the National Guard ahead of a grand jury decision about whether a white police officer will be charged in the fatal shooting of a black 18-year-old in the St. Louis suburb of Ferguson.

Nixon said the National Guard would assist state and local police in case the grand jury’s decision leads to a resurgence of the civil unrest that occurred in the days immediately after the Aug. 9 shooting of Michael Brown by Ferguson Police Officer Darren Wilson.

“All people in the St. Louis region deserve to feel safe in their communities and to make their voices heard without fear of violence or intimidation,” Nixon said in a written statement.

There is no specific date for a grand jury decision to be revealed, and Nixon gave no indication that an announcement is imminent. But St. Louis County Prosecutor Bob McCulloch has said that he expects the grand jury to reach a decision in mid-to-late November.

The U.S. Justice Department, which is conducting a separate investigation, has not said when its work will be completed.